It is known in the art to use cantilevers with electrostatic forces to close an electrical contact. Buck (in U.S. Pat. No. 5,258,591), Frasier (in U.S. Pat. No. 6,548,841), and Yao (in U.S. Pat. No. 5,578,976), for example, all disclose an RF switch that is operated through the application of electrostatic forces. However, these all utilize cantilevered beams that are parallel to a substrate, thereby taking up significant real estate on the chip. Furthermore, these beams can deflect in one direction only. Brandes (in U.S. Pat. No. 6,445,006) discloses a switch with two positions, where the cantilever moves in a line from its rest position forward to touch one contact or back to touch another contact. By these constructions, the cantilever is limited in the number of contacts that it can make. The present invention enables a multi-pole switch that can make selective contact with more than two electrodes, and therefore enables more complex electrical switching operations to be carried out.
It is also known in the art to produce carbon nanotubes that can stand vertically from a substrate. The nanotubes grown by plasma enhanced chemical vapor deposition techniques, described by Ren (U.S. Pat. No. 6,863,942) are freestanding, and can be considered as vertically oriented cantilever beams. I, David Carnahan, in U.S. Pat. No. 6,950,296, described the actuation of these nanotubes using electrostatic and electrodynamic forces to create a multi-element tweezer/grasping device. AC voltages with phase shifts were imposed on the various nanotubes in the device, with the goal of making the nanotubes come together to grasp objects. As described in my U.S. Pat. No. 6,950,296, this invention described sequential contact of individual electrical contacts only through phase lag between multiple cantilever elements.
To increase the utility of a switch, it is the goal of this invention to provide multiple directions of deflection for a cantilever, and more than two contact electrodes for a given cantilever, thus creating a novel multi-pole switch.